Amazon is expected to announce its long-rumoured smartphone at a now-confirmed event on June 18 in Seattle, Digital Spy said.

The device, which many believe to feature an innovative 3D head-tracking system, has been teased by Amazon, with an invite for the event featuring an image of what looks like the back of a smartphone.

Amazon's website now plays host to a special page with the words "Join Amazon's founder Jeff Bezos for our launch event" set across the front.

Perhaps most exciting is a teaser video that sees users playing with the smartphone and reacting to the rumoured eye-tracking tech.

Look carefully and you can see a reflection of the device in one person's glasses, although details of it are impossible to make out.

Previous leaks have seen the Amazon device making an appearance in rendered form, with rumours pointing to a 4.7-inch display and clever gesture-based controls.